<p>You'd be forgiven for thinking that, after 50 years in Hollywood, Steven Spielberg doesn't get nervous when he steps on to a set for the first time.</p><p>But the 74-year-old movie maestro has confessed that he did have some trepidation about West Side Story, which is his first attempt at an all-singing, all-dancing big screen musical.</p><p>West Side Story is in UK cinemas from 10 December.</p>